Front/back control of integrated circuits for flash dual inline memory modules

ABSTRACT

In one implementation, flash memory chips are provided with an operating power supply voltage to substantially match a power supply voltage expected at an edge connector of a dual inline memory module. The one or more of the flash memory chips and a memory support application integrated circuit (ASIC) may be mounted together into a multi-chip package for integrated circuits. The one or more flash memory chips and the memory support ASIC may be electrically coupled together by routing one or more conductors between each in the multi-chip package. The multi-chip package may be mounted onto a printed circuit board (PCB) of a flash memory DIMM to reduce the number of packages mounted thereto and reduce the height of the flash memory DIMM. The number of printed circuit board layers may also be reduced, such as by integrating address functions into the memory support ASIC.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation and claims the benefit of U.S.patent application Ser. No. 14/016,235 filed on Sep. 3, 2013 byinventors Ruban Kanapathippillai, et al., entitled MULTI-CHIP PACKAGEDWITH FLASH MEMORY/SUPPORT APPLICATION SPECIFIC INTEGRATED CIRCUIT FORFLASH DUAL INLINE MEMORY MODULES, pending. U.S. patent application Ser.No. 14/016,235 is a divisional and claims the benefit of U.S. patentapplication Ser. No. 13/457,170 filed on Apr. 26, 2012 by inventorsRuban Kanapathippillai, et al., entitled METHODS OF FLASH DUAL INLINEMEMORY MODULES WITH FLASH MEMORY, now issued as U.S. Pat. No. 8,881,389.U.S. patent application Ser. No. 13/457,170 is a divisional and claimsthe benefit of U.S. patent application Ser. No. 11/876,479 filed on Oct.22, 2007 by inventors Ruban Kanapathippillai, et al., entitled METHODSAND APPARATUS OF DUAL INLINE MEMORY MODULES FOR FLASH MEMORY, now issuedas U.S. Pat. No. 8,189,328. U.S. patent application Ser. No. 11/876,479in turn claims the benefit of U.S. provisional patent application No.60/892,864 filed on Mar. 4, 2007 by inventors Ruban Kanapathippillai, etal., entitled DUAL INLINE MEMORY MODULES FOR FLASH MEMORY, and furtherclaims the benefit of U.S. provisional patent application No. 60/862,597filed on Oct. 23, 2006 by inventors Kumar Ganapathy, et al., entitledEXPANSION OF MAIN MEMORY IN A MULTIPROCESSOR SYSTEM WITH A NON-DRAMMEMORY CONTROLLER TO CONTROL ACCESS TO NON-DRAM TYPE MEMORY.

FIELD

This application relates generally to memory modules for non-volatilememory integrated circuits.

BACKGROUND

Pluggable memory modules are often used to add more dynamic randomaccess memory (DRAM) to a pre-existing computer system. However,sometimes there are space limitations in a system that place heightlimits upon a memory module. Designing a pluggable memory module to haveappropriate electrical characteristics and an appropriate form factorcan be challenging.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1A is a layout of a flash DIMM with flash memory integratedcircuits capable of operating with a different power supply voltage fromthat furnished at the edge connector.

FIG. 1B is a functional block diagram of a flash DIMM with flash memoryintegrated circuits capable of operating with a substantially similarpower supply voltage to that furnished at the edge connector.

FIG. 2A is a functional block diagram of a flash DIMM with flash memoryparts and multi-chip packaged flash memory/data support ASIC parts.

FIG. 2B is a functional block diagram of the multi-chip packaged flashmemory/data support ASIC part of FIG. 2A.

FIG. 3A is a functional block diagram of a flash DIMM with multi-chippackaged flash memory/support ASIC parts and standard address registers.

FIG. 3B is a functional block diagram of the multi-chip packaged flashmemory/support ASIC part of FIG. 3A.

FIG. 4A is a functional block diagram of a flash DIMM with flash memoryparts and multi-chip packaged flash memory/support ASIC parts.

FIG. 4B is a functional block diagram of the multi-chip packaged flashmemory/support ASIC part of FIG. 4A.

FIG. 5A is a functional block diagram of a front side of a flash DIMMwith flash memory parts and multi-chip packaged flash memory/supportASIC parts.

FIG. 5B is a functional block diagram of a back side of the flash DIMMof FIG. 5A.

FIG. 5C is a functional block diagram of the multi-chip packaged flashmemory/support ASIC part of FIGS. 5A-5B.

FIG. 5D is a functional block diagram of an optional multi-chip packagedflash memory/support ASIC part incorporating an address register.

FIG. 6 is a functional block diagram of a multi-chip packaged flashmemory part.

FIG. 7A is a side cutaway view of a first multi-chip packaged flashmemory/support ASIC part.

FIG. 7B is a side cutaway view of a second multi-chip packaged flashmemory/support ASIC part.

FIG. 8A is a functional block diagram of a front side of a flash memoryDIMM with flash memory parts and multi-chip packaged flashmemory/support ASIC parts.

FIG. 8B is a functional block diagram of a back side of the flash DIMMof FIG. 8A.

FIG. 8C is a functional block diagram of the multi-chip packaged flashmemory/support ASIC part shown in FIG. 8A.

FIG. 8D is a functional block diagram of a multi-chip packaged flashmemory part for the flash memory DIMM of FIGS. 8A-8B.

FIG. 9 is a functional block diagram of a memory support ASIC die toprovide data, address, and control support.

DETAILED DESCRIPTION

In the following detailed description, numerous examples of specificimplementations are set forth. However, implementations may includeconfigurations that include less than all or alternatives for thedetailed features and combinations set forth in these examples.

The voltage of the power supply to flash memory integrated circuits maydiffer from the voltage of the power supply to a motherboard of acomputer system. Flash memory integrated circuits may operate andprogram its internal memory cells using one external power supplyvoltage (voltage F), such as three and three-tenths (3.3) volt powersupply. On the other hand, computer systems may furnish a differingexternal power supply voltage (voltage E), such as a one andeighth-tenths (1.8) volt power supply. The differing external powersupply voltage (voltage E) may be externally converted to the powersupply voltage (voltage F) expected by the flash memory integratedcircuits. Some designs of flash memory integrated circuits may becapable of directly operating with the external power supply voltage(voltage E) furnished by the computer system. In those cases where flashmemory integrated circuits are incapable of directly operating with theexternal power supply voltage (voltage E), other circuits in a dualinline memory module (DIMM) can perform DC power conversion to convertthe differing external power supply voltage (voltage E) into the powersupply voltage (voltage F) expected by the flash memory integratedcircuits.

In the design of a non-volatile flash DIMM, the form factor, includingany height limitations, may be considered in the layout design of thenon-volatile DIMM.

Referring now to FIG. 1A, a layout design of a flash dual inline memorymodule (DIMM) 100A with flash memory 133 is illustrated. The flashmemory 133 in this case operates with a different voltage (voltage F)than the external power supply voltage (voltage E) furnished at the edgeconnector 102. The flash DIMM 100A includes on one or both sides of theprinted circuit board 101, a DIMM edge connector 102, power supplyconversion and regulation circuitry 104, a plurality of memory supportcircuits (e.g., data support application specific integrated circuits(ASICs) 115 for data support and commercially available address supportchips or proprietary address support application specific integratedcircuits 117), and flash memory chips 133 coupled together by aplurality of printed circuit board traces, such as trace 160 for examplebetween a pad 150 of the edge connector 102 and a pin of the data ASIC115.

Near an edge the printed circuit board 101 has pads on a front side, aback side, or both front and back sides to form the edge connector 102.The memory module 100A further includes a plurality of printed circuitboard traces 160 (e.g., printed wires) formed on and/or in one or morelayers of the PCB 101 to electrically couple the packaged parts togetherto each other and/or to the pads 150 of the edge connector 102. In oneconfiguration, a DIMM connector 102 may have 240 pins or pads of which72 bits may be used for data, 28 to 40 pins may be used foraddress/control, and the remaining pins or pads may be used for powerand ground.

The plurality of memory support chips, (e.g., the address support chips117 and the data support ASICs 115) may be used to buffer and/orregister addresses, and/or multiplex and de-multiplex data to and fromthe flash memory chips 133.

The flash memory dual inline memory module (FMDIMM) 100A is anon-volatile type of memory module. In particular, the non-volatile typeof memory module may include at least one NOR-gate flash electricallyerasable programmable read only memory (EEPROM) integrated circuit.NAND-gate flash electrically erasable programmable read only memory(EEPROM) integrated circuits may also be used in a flash memory DIMM.Phase shift dynamic random access memory (PSDRAM) may also be used in aflash memory DIMM. Additionally, memory types may be mixed in a flashmemory DIMM. For example, non-volatile memory such as EEPROM flashmemory may be mixed with volatile memory such as standard DRAM memory toform a flash memory DIMM. Non-volatile memory of any type may also begenerally referred to herein as flash memory.

Flash memory may operate using one power supply voltage (voltage F).Computer systems may operate at different power supply voltage (voltageE) such that the signals and power supply expected and provided at theDIMM edge connector when plugged in are in accordance with DIMM edgeconnector power and signal standards. The power supply conversion andregulation circuitry 104 converts the external power supply voltage(voltage E) from the edge of the DIMM connector 102 into the operatingpower supply voltage (voltage F) for the flash memory 133. The powersupply voltages levels to be provided at the edge connector may be inaccordance with Joint Electron Device Engineering Council's (JEDEC)double data rate (DDR) memory standards, JEDEC DDR2 memory standards, orJEDEC DDR3 memory standards for dual inline memory modules. The JointElectron Device Engineering Council is the semiconductor engineeringstandardization body of the Electronic Industries Alliance (EIA), atrade association representing many areas of the electronics industry.For example, in accordance with a DDR2 memory module standard, at theinterface of the connector 102, a power supply voltage of 1.8 volts maybe provided and the circuitry 104 converts the 1.8 volts into a 3.3 voltpower supply expected by some generations of flash memory 133. Asanother example, a power supply voltage of 1.5 volts may be provided atthe edge connector and the circuitry 104 converts the 1.5 volt powersupply into a 1.8 volt power supply expected by another generation offlash memory 133.

Both of the power supplies with the different power supply voltages maybe coupled into the address and data support ASICs 117,115 so that theycan translate signals between each signaling standard. For example, atthe interface of the connector 102, 1.8 volt standard signals may beexpected while some generations of flash memory 133 may be expecting 3.3volt standard signals at the chip interface. In this case, the addressand data support ASICs 117,115 may receive 1.8 volt standard signals foraddress/control and data from the edge connector and convert them into3.3 volt standard signals for the flash memory. Additionally, theaddress and data support ASICs 117,115 may receive 3.3 volt standardsignals for data from the flash memory and convert them into 1.8 voltstandard signals for driving data out onto the edge connector. Thus, theaddress and data support ASICs 117,115 may perform voltage translationfor signals between the edge connector and the flash memory.

The power supply conversion and regulation circuitry 104 uses space onthe printed circuit board (PCB) 101 as shown in FIG. 1A. Additionally,the address and data support ASICs and chips 117,115 take up space onthe PCB 101 in a row along the connector 102 adding further to theheight of the DIMM 100 as illustrated in FIG. 1A.

The height added to the DIMM 100A by power supply conversion andregulation circuitry 104 and the address and data support ASICs andchips 117,115 may be so much that it exceeds one unit (1U) standardheight of thirty millimeters (mm). As a result of the larger height, theflash DIMM 100A may not be usable in a number of computing systems thatuse one unit standard height DIMMs.

The flash memory 133 can be redesigned so that it can operate using theexternal voltage supplied at the DIMM edge connector instead so that thepower supply conversion and regulation circuitry 104 may be eliminatedfrom the DIMM 100A. Moreover, the packaged flash memory 133 may onlycontain a single die. The flash memory coupled to the DIMM may bere-packaged to include a plurality of flash memory die in one package toincrease memory capacity and/or reduce the number of packaged partsmounted to the PCB of the DIMM. With fewer parts mounted to the PCB ofthe DIMM, the height of the DIMM may be reduced.

Moreover, the address and/or data support chips 117,115 may be furtherpackaged together with flash memory to reduce the height of a DIMM(e.g., a 16 giga-byte DIMM) down to thirty millimeter for one unitstandard height systems. Various configurations of flash memory chipsand address and data support ASICs may also be used to reduce the numberof PCB traces and further reduce the height of the PCB and DIMM. In thismanner, a flash DIMM may be more widely sold and used to achieveeconomies of scale.

Referring now to FIG. 1B, a block diagram of a flash memory DIMM(FMDIMM) 100B is illustrated. Several address/control buffer ASICs maybe integrated into a multi-chip package or multi-chip module (MCM) toform a multi-chip packaged address/control ASIC part 157 to reduce theheight of the PCB. A plurality of flash memory dice or die (e.g., four)may be mounted together into one multi-chip package or multi-chip module(MCM) to form a multi-chip packaged flash memory part 118 to reduce theheight of the PCB. In other implementations, a support ASIC die and oneor more flash memory dice may be mounted together into one multi-chippackage or multi-chip module (MCM) to form a multi-chip packaged flashmemory/support ASIC part to further reduce the number of packaged partsmounted to the PCB of a FMDIMM.

Previously, an integrated circuit package with multiple chips mountedtherein may have been referred to as a hybrid package or a multi-chipmodule. More recently, hybrid packages and multi-chip modules arereferred to as multi-chip packages (MCP) or chip-scale packages (CSP),ignoring whether or not the chips are stacked upon each other or not.

The data support ASIC part 155 multiplexes and de-multiplexes the datalines of the plurality of flash memory die with an external data bus. Inone implementation, a four to one bus multiplexer and a one to four busdemultiplexer is provided by the data support ASIC part 155.

The flash memory DIMM 100B includes a plurality of flash memory chips118 with other memory support application integrated circuit (ASIC)chips that operate with a power supply that matches the expected signallevels and power supply of the computer system into which the FMDIMM100B may be plugged. In one implementation, the chips use a one andeight-tenths (1.8) volt power supply. By operating with a power supplythat matches the expected signal levels and power supply of the computersystem into which the FMDIMM 100B may be plugged, the power supplyconversion and regulation circuitry 104 can be eliminated to reduce theheight of the PCB and DIMM.

The FMDIMM 100B is configured with two ranks (rank zero and rank one) offlash memory each having eighteen flash memory chips 118 with addresslines 140A,140B,141A,141B coupled into each flash memory chip 118 toaddress memory space. Rank zero and rank one may each have nine flashmemory chips 118 mounted onto the front of the PCB and nine flash memorychips 118 mounted onto the back side of the PCB for a total ofthirty-six flash memory packages 118 being included as part of theFMDIMM 100B. As discussed further herein, a plurality of flash memoryintegrated circuits may be packaged into one multi-chip package such asan MCM integrated circuit package to further reduce the number ofpackages mounted to the printed circuit board (PCB) of the FMDIMM.

The flash memory DIMM 100B further includes address/control support ASICparts 157 and data support ASIC parts 155 coupled together and to theflash memory parts 118 as illustrated. The data support ASIC parts 155may be mounted to the printed circuit board in a row next to the edgeconnector 102. The address/control support ASIC parts 157 may be mountedto the printed circuit board between a left plurality of flash memoryparts 118 in each row and a right plurality of flash memory parts 118 ineach row. There may be five memory slices 128A-128E to one side of theaddress/control support parts 157 and four memory slices 128F-128I tothe other side of the address support parts 157.

The flash memory DIMM 100B may have four address/control support ASICparts 157, two of which may be mounted on the front side and two ofwhich may be mounted on the back side of the PCB. Two address/controlsupport ASICs 157, each on opposite sides of the PCB, may be providedfor each rank or row of flash memory. Each of the address/controlsupport ASICs 157 may receive address lines 145 that are used toregister or latch address/control information over two clock cycles.Typically, the lower address bits are sent in the first clock cycle andthe upper address bits/control bits are sent in the second clock cycle.A rank control signal may be used to designate which rank of memory theaddress information is for. The address/control information may bedecoded to generate address lines 140A-140B for rank zero, address lines141A-141B for rank one, and multiplexer control signals 142A-142Bcoupled to the data support ASIC parts 155. The address lines 141A-141B,140A-140B for memory ranks zero and one may be routed between front andback sides of the PCB such as by means of through-holes, vias, orwrapping around an edge (e.g. bottom or top edge) of the PCB. Half ofthe address lines may be generated by address support/control ASICs 157on a front side of the PCB and the other half of address liens may begenerated by address/control support ASICs 157 on the back side of thePCB. The address/control support ASICs 157 may buffer and broadcast theaddresses to the flash memory parts 118 to reduce loading of the addresslines at the edge connector.

Each side may have nine memory slices or columns 128A-128I with eachmemory slice 128 including a flash memory chip 118 in rank one, a flashmemory chip 118 in rank zero, and a data support ASIC 155 coupledtogether as shown in FIG. 1B.

Each of the data support ASICs 155 may include a four to one multiplexerand one into four demultiplexer so that bidirectional data can becommunicated between a sixteen bit data bus 138 in each slice and a fourbit data bus 139 into the connector 102. That is, sixteen bits of datain bus 138 may be multiplexed out to four bits of the data bus 139 overfour consecutive cycles when reading out data from the FMDIMM 100B. Whenwriting data into the FMDIMM 100B, four bits of data on the data bus 139from each of four consecutive data cycles may be de-multiplexed intofour of the sixteen bits of the data bus 138.

FIG. 2A is a functional block diagram of another configuration of aflash memory dual inline memory module (FMDIMM) 200. The flash memorydual inline memory module (FMDIMM) 200 includes a plurality ofmulti-chip packaged flash memory parts 118, a plurality of multi-chippackaged flash memory/data support ASIC parts 210, and a plurality ofplurality of address support ASICs 157 coupled together as shown.

The data support ASIC die is of a relatively small die size so that itcan be integrated with a flash memory chip into a multi-chip package210. The multi-chip packaged flash memory/data support ASIC part 210including flash memory may be used in one rank of memory, rank zero forexample. This removes a number of the data support ASIC packages fromthe printed circuit board so that its height may be reduced. However aplurality of address support ASICs 157 may still be employed in theFMDIMM 200 so that the address pins/pads of the connector 102 are routedto both ranks (rank one and rank zero) independently, such that extraprinted circuit board layers may be used to route the traces over otheraddress lines.

The FMDIMM 200 includes a plurality of memory slices 228A-228I(generally referred to as memory slice 228) on each side. Each memoryslice 228 includes one packaged flash memory chip 118 and one multi-chippackaged flash memory/data support ASIC packaged part 210. The data onbus 139 may be routed through the multi-chip packaged flash memory/datasupport ASIC part 210 to and from the flash memory chip 118 over the bus138.

FIG. 2B is a functional block diagram of the multi-chip packaged flashmemory/data support ASIC part 210 of FIG. 2A. The multi-chip packagedflash memory/data support ASIC part 210 includes one or more unpackagedflash memory dice 118′ and an unpackaged data support ASIC die 155′coupled together as shown. The unpackaged flash memory and theunpackaged data support ASIC dice are mounted to a substrate of themulti-chip packaged with traces of the bus 138 routed between each. Thefour bit bus 139 is coupled into the data support ASIC chip 155′. Witheighteen multi-chip packaged flash memory/data support ASIC parts 210 ina rank, eighteen data support ASIC dice 155′ are used per FMDIMM 200.

Referring now to FIG. 3A, a functional block diagram of anotherimplementation of a flash memory DIMM (FMDIMM) 300 is illustrated. Theflash memory DIMM 300 includes a plurality of multi-chip packaged flashmemory/support ASIC parts 310A-310B (collectively referred to by thereference number 310) and standard DDR2 address registers 301-302coupled together. A portion of the address/control support ASIC 157 iscombined with the data support ASIC 155 into one die and mounted withflash memory dice into a multi-chip package (MCP) to form the multi-chippackaged flash memory/support ASIC part 310. This eliminates the cost ofhaving two different ASIC parts by using one ASIC and a standard off theshelf address register chip. Moreover, the number of address lines maybe reduced and the number of PCB board layers may be reduced to lowercost of manufacturing the FMDIMM. As the multi-chip packaged flashmemory/support ASIC part 310 provides data, address, and controlsupport, it may also be referred to as a multi-chip packaged flashmemory/address, control, & data support ASIC part 310.

The FMDIMM 300 includes a plurality of memory slices 328A-328I on eachside. Each memory slice 328 includes a pair of multi-chip packaged flashmemory/support ASIC parts 310A-310B. The data on bus 139 may be routedthrough the multi-chip packaged flash memory/support ASIC part 310A toand from the multi-chip packaged flash memory/support ASIC part 310Bover the bus 138. The multi-chip packaged flash memory/support ASIC part310B may be substantially similar to the multi-chip packaged flashmemory/support ASIC part 310A. However, the multi-chip packaged flashmemory/support ASIC packaged part 310B is not directly coupled to theconnector 102 of the DIMM 300 so it may be simplified and with databeing passed to it, it may operate somewhat differently.

The multi-chip packaged flash memory/support ASIC packaged part 310Apasses data from the edge connector 102 through it to the multi-chippackaged flash memory/support ASIC packaged part 310B over the bus 138.Similarly, the multi-chip packaged flash memory/support ASIC packagedpart 310A may receive data from the multi-chip packaged flashmemory/support ASIC packaged part 310B on the bus 138 and pass itthrough it to the edge connector 102.

The address lines 145 from the edge connector 102 are coupled into theaddress register 302. The address may be passed from the addressregister 302 to the address register 301 over the address bus 345. Eachof the address registers drives address lines out each side. The addressregister 301 drives address lines 340A to the slices 328A-328E andaddress lines 340B to the slices 328F-328I. The address register 302drives address lines 341A to the slices 328A-328E and address lines 341Bto the slices 328F-328I. The number of address lines is reduced becausethe addresses are buffered and fully formed in the support ASIC residingin the packages 310A-310B reducing the routing traces and the space usedon the PCB. Moreover with fewer address lines, the multi-chip integratedcircuit packages have fewer pins which may reduce packaging costs. Also,the address bus width is cut in half by sending the complete addressover 2 cycles reducing the number of address traces on the PCB, thenumber of PCB board layers may be reduced as a result.

FIG. 3B is a functional block diagram of the multi-chip packaged flashmemory/support ASIC part 310A of FIG. 3A. The multi-chip packaged flashmemory/support ASIC part 310A includes one or more unpackaged flashmemory dice 118′ and an unpackaged address/control/data support ASIC die350 coupled together as shown. The chips are mounted to a substrate ofthe multi-chip package with traces of the data bus 138 and the flashaddress bus 348 routed between each as illustrated. The bit data busbits 139 and the input address bus 341 are coupled to theaddress/control/data support ASIC chip 350. As previously mentioned, aportion of the function of the address/control support ASIC 157 may beintegrated with the function of the data support ASIC 155 into one chip,the address/control/data support ASIC chip 350. However with extrafunctionality, the address/control/data support ASIC chip 350 requiresthe use of more input/output pins.

Additionally, with the pass through of data, addresses, and controlsignals from the multi-chip packaged flash memory/support ASIC part 310Ato the multi-chip packaged flash memory/support ASIC part 310B, the datalatency into and out of the FMDIMM may be increased by one clock cycle.

Referring now to FIG. 4A, a functional block diagram is illustrated ofanother configuration of a flash memory DIMM 400. The flash memory DIMM400 includes a plurality of multi-chip packaged flash memory/supportASIC parts 410 and address registers 301-302 coupled together. As themulti-chip packaged flash memory/support ASIC part 410 provides data,address, and control support, it may also be referred to as a multi-chippackaged flash memory/address, control, & data support ASIC part 410.

The FMDIMM 400 includes a plurality of memory slices 428A-428I on eachside. In one implementation, nine memory slices 428A-428I on each sideare divided by the address registers 301-302 into five and four memoryslices into a row. Each memory slice 428 includes a pair of multi-chippackaged flash memory/support ASIC packaged parts 410. The data bus 139is coupled to each of the multi-chip packaged flash memory/support ASICpackaged parts 410 so that a pass through bus 138 is not needed, therebyreducing the number of routing traces on the printed circuit board.Thus, the FMDIMM 400 has a data bus shared between memory ranks zero andone. With the number of lines of an address bus cut in half and thenumber of lines of a data bus significantly reduced, the number oflayers in the PCB may be reduced as well.

The address register 301 drives 20 address lines 340A to the slices428A-428E and 20 address lines 340B to the slices 428A-428I coupling tothe upper row multi-chip packaged flash memory/support ASIC packagedparts 410 in each. The address register 302 drives 20 address lines 341Ato the slices 428A-428E and 20 address lines 341B to the slices428F-428I coupling to the lower row multi-chip packaged flashmemory/support ASIC packaged parts 410 in each.

FIG. 4B is a functional block diagram of the multi-chip flashmemory/support ASIC packaged part 410 of FIG. 4A. The multi-chippackaged flash memory/support ASIC part 410 includes one or moreunpackaged flash memory dice 118′ and an unpackaged address/control/datasupport ASIC die 450 coupled together as shown. The dice are mounted toa substrate of the multi-chip packaged package with traces of the databus 438 and an address bus 348 routed between each as illustrated. Thefour bit data bus 139 and the address bus 341 are coupled to theaddress/control/data support ASIC die 450. As previously mentioned, aportion of the function of the address/control support ASIC 157 may beintegrated with the function of the data support ASIC 155 into one die,the address/control/data support ASIC die 450. The extra functionality,the address/control/data support ASIC die 450 may use additionalinput/output pins. Moreover, the address/control/data support ASIC die450 is functionally more complex with more gates and thus has a largerdie size and may cost more to manufacture. If the address/control/datasupport ASIC die 450 is implemented as a programmable logic device, itis a complex programmable logic device (CPLD). For thirty-six multi-chippackaged parts 410 in each FMDIMM, there may be a total of thirty sixaddress/control/data support ASIC dice on a PCB, one in each package.

In comparison, the multi-chip packaged flash memory/support ASIC part410 may have fewer pins that the MCP flash memory/support ASIC part 310Aas the pass through bus 138 need not be supported by it. Instead, thedata bus 438 is internal within the multi-chip packaged flashmemory/support ASIC part 410. With fewer pins, the multi-chip packagedflash memory/support ASIC part 410 may cost less. The FMDIMM 300 mayapply less parasitic load onto the edge connector 102 than the FMDIMM400. However without the shared wider data bus, there is less routingtraces on the printed circuit board as the data bus 138 is not used topass data between parts in a slice. However, there is additional loadand stubs applied to the DDR memory bus into which the FMDIMM plugsinto. Moreover, there is still one clock cycle additional latency in theFMDIMM 400, due to the address registers 301-302.

Reference is now made to FIGS. 5A-5D. FIGS. 5A and 5B respectivelyrepresent a functional block diagram of a front side 500F and a backside 500B of another implementation of a FMDIMM 500. The front side 500Fof the FMDIMM 500 includes multi-chip packaged flash memory parts 518F,and 518B, and multi-chip packaged flash memory/support ASIC parts 510F,and an address register 301F coupled together as shown. In oneimplementation, the address register 301F is an off-the-shelf orstandard DDR2 memory address register. As the multi-chip packaged flashmemory/support ASIC part 510F provides data, address, and controlsupport, it may also be referred to as a multi-chip packaged flashmemory/address, control, & data support ASIC part 510F.

The FMDIMM 500 includes a plurality of memory slices 528A-528I on oneside and a plurality of memory slices 528I′-528A′ on the other side ofthe FMDIMM 500. In one implementation, there are nine memory slices528A-528I on the front side, and nine memory slices 528I′-528A′ on theback side of the DIMM. A front side address register 301F may beconnected to the nine front side packages 510F through the traces540A-540B. A back side address register 301B may be connected to thenine back side packages 510B through the traces 540A′-540B′.

Each front side memory slice 528 includes a multi-chip packaged flashmemory part 518F and a multi-chip packaged flash memory/support ASICpart 510F coupled together as shown by a pass through data bus 538F anda pass through address/control bus 548F. The front side address/controlbus 548F in each slice is also routed through vias 568 to the back sideof the FMDIMM 500 connecting to a multi-chip packaged flash memory part518B on the back side. A back side address/control bus 548B may berouted from the back side to the front side of the FMDIMM 500 such asthrough vias or feed-throughs (or alternatively by wrapping around anedge of the PCB) and is coupled into the front side flash memory part518F.

Front side data bus bits 139F, a subset of the respective data bits ofthe edge connector 102, are coupled to each of the multi-chip packagedflash memory/support ASIC parts 510F in each memory slice 528A-528I onthe front side. Each memory slice couples to a respective subset of thetotal data bits at the edge connector of the DIMM. This may reduce thenumber of data bus signals routed over each side of the chip to reducethe size of the PCB, reduce the number of layers in the PCB, and/orreduce the loading on the edge connector 102. With the number of addresslines routed across the FMDIMM being reduced as well, the size of thePCB and the number of layers in the PCB may be further reduced.

The front side address register 301F receives address lines from theconnector 102 and registers an address or control signals that may bemultiplexed on the address lines. The address register 301F can thendrive out the address or control signals on the address/control lines540A to the slices 528A-528E and address/control lines 540B to theslices 528F-528I coupling to the multi-chip packaged flashmemory/support ASIC packaged parts 510F in each.

A front/back signal line 541A is coupled into the slices 528A-528E and afront/back signal line 541B to the slices 528F-528I coupling to thehybrid flash memory/ASIC packaged parts 510F in each. The front/backsignal line 541A is tied to power (VDD) or to ground (VSS) in thepackage or externally. The front/back signal line 541A tells the memorysupport ASIC if it is to operate in a front mode or a back mode. Thefront/back signal line 541A signal will be used by the memory supportASIC to send upper or lower address bits to flash memory part 518F aboveit in the memory slice 528. The front/back signal line tells the ASIC510F to send the upper 16 or lower 16 address bits to the flash memorypackages 518 in the top rank. In one implementation, the front/backsignal lines 541A-541B are tied to power VDD for the front side flashmemory 518F and the front side hybrid part 510F to operate in a frontside mode on the FMDIMM 500.

FIG. 5B illustrates a back side 500B of the PCB and the flash memoryDIMM 500 mirroring the front side of the FMDIMM 500 so that the PCBtraces are further reduced to minimize the size of the printed circuitboard. The back side of the flash memory DIMM 500 includes back sideflash memory parts 518B, hybrid flash memory/ASIC parts 510B, and anaddress register 301B coupled together as shown. In one implementation,the address register 301B is an off-the-shelf or standard DDR2 memoryaddress register.

The back side memory slice 528A′ on the right is parallel to the frontside memory slice 528A. The back side memory slice 528I′ on the left isparallel to the front size memory slice 528I. The flash memory parts518F-518B may be mounted substantially in parallel to each other onopposite sides of the PCB. Similarly, the hybrid parts 510F and 510B maybe mounted substantially in parallel to each other and the flash memoryparts 518F and 518B on opposite sides of the PCB to minimize the lengthand number of PCB routing traces.

In each memory slice 528I′-528A′, the front side address/control bus548F is also routed through vias 568 to the back side of the FMDIMM 500and coupled into the backside flash memory parts 518B. The back sideaddress/control bus 548B generated by the back side hybrid flashmemory/memory support ASIC part 510B is coupled into the back side flashmemory part 518B and routed from the back side to the front side of theFMDIMM to couple into the front side flash memory part 518F.

A four bit data bus 139B of a respective four data bits of the connector102 is coupled to the hybrid flash memory/ASIC packaged part 510B. Withaddress lines routed across the FMDIMM being further reduced, the sizeof the PCB and the number of layers in the PCB may be reduced.

The address register 301B receives 20 address lines from the connector102 and registers the address to then drive 20 address lines 540A′ tothe slices 528F′-528I′ and 20 address lines 540B′ to the slices528A′-528E′ coupling to the hybrid flash memory/ASIC packaged parts 510Bin each. The address register and data support ASIC may be combined intoone address and data support ASIC 510′ in one implementation to furtherreduce the number of packages on the PCB (see FIG. 5D).

A front/back signal line 541A′ is coupled into the slices 528A′-528E′and a front/back signal line 541B′ to the slices 528F′-528I′ coupling tothe hybrid flash memory/ASIC packaged parts 510B in each. The front/backsignal lines 541A′-541B′ are similar to the front/back signal lines541A-541B previously described. However in one configuration, thefront/back signal lines 541A′-541B′ are tied to ground VSS asillustrated for the back side flash memory 518B and the back side hybridpart 510B to operate in a back side mode on the FMDIMM 500.

The back side flash memory parts 518B, MCP flash memory/support ASICparts 510B, and the address register 301B are mirror images of theirfront side counter parts 518F, 510F, 301F to reduce conductive traces ona printed circuit board of the memory module and the number of layersneeded. That is, the pinouts are mirror images. A mirror imaged pinoutmay be accomplished in a number of ways.

In one implementation, the package for the flash memory part 518B may beconstructed to use the same dice as used in the front flash memory part518F, but the package for the back side flash memory part 518B may beinternally wired differently to mount to the backside of the memorymodule and mirror the front side flash memory part 518F on a front sideof the memory module.

In another implementation, the integrated circuit die for the back sidemay be altered from the front side die. That is, the pinout of the flashmemory die for the back side parts 518B may be altered to mirror thepinout of the front side flash memory parts 518F. In one implementation,the layouts of the back side flash memory parts differ physically fromthe layouts of the front side flash memory parts to mirror the pinout.In another implementation, a front/back control signal may be tiedlogically high or low and used to electronically alter the pinoutconfiguration to provide a mirrored pinout.

While the packages for the flash memory parts 518F and 518B have beendescribed as having mirrored pinouts in different implementations, themulti-chip packaged flash memory/support ASIC parts 510F, 510B and theaddress register parts 301F, 301B may be similarly implemented toprovide mirrored pinouts for the respective front and back sides of theFMDIMM 500.

For example, a front/back control signal 541A, 541B and 541A′, 541B′ maybe used to electronically alter the pinout configuration of multi-chippackaged flash memory/support ASIC parts 510F, 510B to provide amirrored pinout. In response to the front/back control signal, the chipselectronically alter their pinout configurations by rerouting signallines to different input/output pads on the chip. The front/back controlsignal 541A, 541B may be tied logically high to VDD routing the signalsinto a first routing pattern to provide a front side pinout for themulti-chip packaged flash memory/support ASIC parts 510F mounted to thefront of the DIMM. The front/back control signal 541A′, 541B′ may betied logically low to VSS routing the signals into a second routingpattern to provide a mirroring back side pinout for the multi-chippackaged flash memory/support ASIC parts 510B mounted to the back sideof the DIMM.

Referring now to FIG. 5C, a functional block diagram of the multi-chippackaged flash memory/support ASIC part 510 is illustrated. Themulti-chip packaged flash memory/support ASIC part 510 includes one ormore unpackaged flash memory dice 118′ and an unpackagedaddress/control/data support ASIC die 550 coupled together as shown. Thechips are mounted to a substrate of the multi-chip package with tracesof the data bus 538 and the address bus 348 routed between each asillustrated. A plurality of data bus bits 139 and a plurality of addressbus bits 341 are coupled to the address/control/data support ASIC die550. The address/control buses 548F and 548B to Rank1 are shared betweenthe front and back Rank zero flash memory packages 518 so each packageonly outputs one multiplexed address/control bus to reduce the pincount.

The address/control/data support ASIC die 550 has an address/control bus548 that is shared with the flash memory chip 518 in each respectivememory slice for addressing the top rank (rank one) of flash memory 518.The data bus 538 is extended out of the multi-chip package to be sharedwith the flash memory chip 518 in each respective memory slice as well.

A front/back signal line 541 is coupled into ASIC die 541. Thefront/back signal line 541 is tied to power (VDD) or to ground (VSS) inthe package 510 or externally. The front/back signal line 541 tells thememory support ASIC 550 if it is to operate in a front mode or a backmode. The front/back signal line 541 signal will be used by the memorysupport ASIC to send upper or lower address bits to the flash memorypart 518 above it in the memory slice 528. The front/back signal linetells the ASIC 550 to send the upper 16 or lower 16 address bits on thebus 548 to the flash memory packages 518 in the top rank.

As previously mentioned, a portion of the function of the addresssupport ASIC 157 may be integrated with the function of the data supportASIC 155 into one chip, the address/control/data support ASIC chip 550.However with the extra functionality, the address/control/data supportASIC chip 550 requires extra input/output pins. Moreover, theaddress/control/data support ASIC chip 550 is functionally more complexwith more gates and thus has a large die size and a greater cost. Ifimplemented as a programmable logic device, it is a complex programmablelogic device (CPLD). For two ranks with eighteen multi-chip packagedflash memory/support ASIC parts 510 in the bottom rank, there are atotal of eighteen CPLD ASICs for one FMDIMM 500.

Additionally, with the pass through of data and addresses, the datalatency into and out of the FMDIMM may be increased by one clock cycle.

In one implementation, the memory support ASIC 550 is integrated amulti-chip package such as a multi-chip module (MCM) integrated circuitpackage.

The FMDIMM 500 may use one standard off the shelf DDR2 address registerpart 301 for both ranks of memory. As the buses 538 and 548 can bereadily routed between parts in each slice, it may be easy to routeconductors between all of the parts mounted onto the PCB of the FMDIMM500. This may result in area or space savings on the PCB to furtherreduce the size. Moreover, the flash memory 518 for the top rank, (rankone), may be packaged in a standard multi-chip module integrated circuitpackage. The package part 510 has extra pins added to its package toprovide the pass-through of data, address, and controls to the flashmemory part 518.

Referring now to FIG. 5D, a functional block diagram of the multi-chippackaged flash memory/support ASIC part 510′ is illustrated. Themulti-chip packaged flash memory/support ASIC part 510′ is similar tothe multi-chip packaged flash memory/support ASIC part 510. However, themulti-chip packaged flash memory/support ASIC part 510′ includes anintegrated address register 301 to avoid the separate packaged addressregisters 301F and 301B in one implementation to further reduce thenumber of packages mounted on the PCB.

The ASIC die 550′ receives the address bits 145 from the connector 120and couples them into the address register 301. The ASIC die 550′buffers the address signals and drives them out onto the address lines540A and 540B to the other multi-chip packaged flash memory/support ASICparts 510 in the row.

If additional functionality is incorporated into the memory support ASICto handle each row of flash memory parts on both front and back sides,the number of multi-chip packaged flash memory/support ASIC parts 510mounted on the DIMM may be reduced. For two ranks with only ninemulti-chip packaged flash memory/support ASIC parts in the bottom rank,there are a total of nine CPLD ASICs for one FMDIMM.

Referring now to FIG. 6, a block diagram of a multi-chip packaged flashmemory part 118,518 is illustrated. The flash memory part includes oneor more unpackaged flash memory die 118′ (e.g., a monolithicsemiconductor substrate) mounted to a package substrate 601 of anintegrated circuit package 600. In one implementation, the integratedcircuit package 600 is a standard multi-chip module integrated circuitpackage. Address and/or control lines 141,548F,548B are coupled to theone or more unpackaged flash memory dice 118′. Data lines 138,538 arealso coupled to the one or more unpackaged flash memory dice 118′.

Referring now to FIGS. 8A and 8B represent a functional block diagram ofa front side 800A and a back side 800B of an FMDIMM 800 is illustrated.The FMDIMM 800 includes multi-chip packaged flash memory parts 818F and818B respectively on front and back side, multi-chip packaged flashmemory/support ASIC parts 810F on the front side, and an addressregister 301 on the front side coupled together as shown. In oneimplementation, the address register 301F is an off-the-shelf orstandard DDR2 memory address register. As the multi-chip packaged flashmemory/support ASIC part 810F provides data, address, and controlsupport, it may also be referred to as a multi-chip packaged flashmemory/address, control, & data support ASIC part 810F.

The FMDIMM 800 includes a plurality of memory slices 828A-828I on oneside (e.g., front side 800F) and a plurality of memory slices828I′-828A′ on the other side (e.g., back side 800B) of the FMDIMM 800.In one implementation, there are nine memory slices 828A-828I on thefront side, and nine memory slices 828I′-828A′ on the back side of theDIMM. The address register 301F is connected to the nine multi-chippackaged flash memory/support ASIC part 810F on via traces 840.

Each front side memory slice 828 includes a multi-chip packaged flashmemory part 818F and a multi-chip packaged flash memory/support ASICpart 810F coupled together as shown by a pass through address low/databus 838 and a pass through address high/control bus 848. The addresshigh/control bus 848 is also routed through vias or feed-throughs 868 tothe back side of the FMDIMM 800 connecting to the multi-chip packagedflash memory parts 818B mounted on the back side 800B in each respectiveslice. The address low/data bus 838 is also routed through vias orfeed-throughs 869 to the back side of the FMDIMM 800 connecting to themulti-chip packaged flash memory parts 818B mounted on the back side800B in each respective slice.

Data bus bits 139F of respective data bits of the connector 102 arecoupled to the multi-chip packaged flash memory/support ASIC part 810F.

The address register 301F receives address lines from the connector 102and registers the address to then drives address lines 840A to theslices 828A-828I coupling to the hybrid flash memory/support ASICpackaged parts 810F in each. With address lines routed across the FMDIMMbeing further reduced, the size of the PCB and the number of layers inthe PCB may be reduced

FIG. 8B illustrates a back side 800B of the PCB and the flash memoryDIMM 800. The back side of the flash memory DIMM 800 includes back sideflash memory parts 818B in each respective memory slice 828I′-828A′ asshown. The memory slices 828I′-828A′ on the back side mirror the memoryslices 828A-828I on the front side so that the PCB traces to minimizethe size of the printed circuit board.

The back side memory slice 828A′ on the right is behind the front sidememory slice 828A. The back side memory slice 828I′ on the left isbehind the front size memory slice 828I. The flash memory parts 818F and818B may be mounted substantially in parallel to each other on oppositesides of the PCB. Similarly, the MCP flash memory/support ASIC parts810F may be mounted substantially in parallel to flash memory parts 818Bon opposite sides of the PCB to minimize the length and number of PCBrouting traces.

In each memory slice 828I′-828A′ on the back side 800B, the addresshigh/control bus 848 and the address low/data bus 838 are routed fromthe front side to the back side through the vias or feedthroughs 868 and869 respectively. On the back side 800B, portions of the addresshigh/control bus 848 and the address low/data bus 838 are coupled intothe two rows of backside flash memory parts 818B.

On the back side flash memory parts 818B, such as address/high controlpins, may have signal assignments which mirror images of their frontside counter parts to reduce conductive traces on a printed circuitboard of the memory module and the number of layers needed. That is, oneor more of the pin outs of the back side flash memory parts 818B aremirror images of the front side flash memory parts 818F. Various ways ofimplementing mirror imaged pinouts were previously described and areincorporated here by reference.

Referring now to FIG. 8C, a functional block diagram of the multi-chippackaged flash memory/support ASIC part 810 is illustrated. Themulti-chip packaged part 810 includes one or more unpackaged flashmemory dice 118′ and an unpackaged address/control/data support ASIC die850 coupled together as shown. The chips are mounted to a substrate ofthe multi-chip package with traces of the address low/data bus 838 andaddress high/control bus 848, 848I routed between each as illustrated.Data bus bits 139 and a multiplexed address/control bus 840 are coupledinto the address/control/data support ASIC die 850.

The support ASIC 850 drives out the higher address bits and control bitsdirectly to the flash memory die(s) over internal signal lines 848Iwhile driving out higher address bits and control bits for the otherfront side flash memory packages 818F and the back side flash memorypackages 818B on bus 848.

Within the FMDIMM 800, the row of components on the front and back sidesclosest to the edge connector 102 may be referred to as memory rankzero. The upper row of components on the front and back sides furthestaway from the edge connector 102 may be referred to as memory rank one.There are separate control signals for each rank, and shared addresshigh signal lines which are shared between the two memory ranks. Forexample, the subset of the bits of the address/control bus 848 whichpertain to memory rank zero are shared between the front and back memoryrank zero flash memory in the multi-chip packages 810 and 818B so thateach package connects to one address/control bus to reduce the printedcircuit board trace count. Similarly, a subset of the address/controlbus which connects to rank one is respectively shared between the frontand back rank one flash memory parts 818F and 818B.

The address/control/data support ASIC die 850 has an address/control bus848 that is shared with the flash memory chip 818F on the front side andthe flash memory packages 818B on the back side in each respectivememory slice. The address low/data bus 838 is extended out of themulti-chip packaged integrated circuit package to be shared with theflash memory in the multi-chip packages 810 and 818F on the front sideconnecting to half the bus 838 and the multi-chip flash memory packages818B on the back side connecting to the other half of the bus 838 ineach respective memory slice as well.

As previously mentioned, a portion of the function of the addresssupport ASIC 157 may be integrated with the function of the data supportASIC 155 into one chip, the address/control/data support ASIC chip 850.However with the extra functionality, the address/control/data supportASIC chip 850 requires extra input/output pins. Moreover, theaddress/control/data support ASIC chip 850 may be functionally morecomplex with more gates and thus may have a large die size and bemanufactured at greater cost. If implemented as a programmable logicdevice, it is a complex programmable logic device (CPLD). For two rankswith nine MCP flash memory/support ASIC parts 810 in the bottom rank,there are a total of nine CPLD ASICs for one FMDIMM 800.

Additionally, with the pass through of data and addresses through theData, Address and Control support ASIC die 850, the data latency intoand out of the FMDIMM may be increased by one or more clock cycles.

The FMDIMM 800 may use one standard off the shelf DDR2 address registerpart 301 for both ranks of memory. As the address register part 301connects to the front support ASIC parts 810, and as buses 838 and 848are routed between parts in each slice, there may be area or spacesavings on the PCB to further reduce its size. Moreover, the flashmemory parts 818F on the front side and the flash memory parts 818B onthe back side may be packaged in a multi-chip package. The multi-chippackaged flash memory/support ASIC part 810 has extra pins added to itspackage to provide data pass-through of data signals, addresspass-through of address signals, and control pass-through of controlsignals to the flash memory parts 818F,818B.

Referring now to FIG. 8D, a block diagram of a multi-chip packaged flashmemory part 818 is illustrated. The flash memory part 818 includes oneor more unpackaged flash memory die(s) 118′ (e.g., a monolithicsemiconductor substrate) mounted to a package substrate 801 of anintegrated circuit package 800. The flash memory dice may be NOR-gateflash electrically erasable programmable read only memory (EEPROM)integrated circuit in some implementations.

In one implementation, the integrated circuit package 800 may be amulti-chip module integrated circuit package. Selected address/controllines of the address high/control bus 848 are coupled into the one ormore unpackaged flash memory dice 118′ depending upon the mounting(front or back) of the part 818 and the rank of memory (e.g., rank oneor zero) it is to operate on the DIMM. Selected address/data lines ofthe address low/data bus 838 are also coupled into the one or moreunpackaged flash memory dice 118′ depending upon the mounting (front orback) of the part 818 and the rank of memory (e.g., rank one or zero) itis to operate on the DIMM.

Referring now to FIG. 9, a functional block diagram of a flash memorysupport ASIC die 900 is illustrated. The flash memory support ASIC die900 may provide data, address, and control support for the flash memoryon a DIMM. The flash memory support ASIC die 900 includes anaddress/control block 902, a data path buffer 904, a datamultiplexer/de-multiplexer 906, and clock/status block 908 coupledtogether as shown.

The address/control block 902 is coupled to the address/control bus 913to receive input addresses and control signals that may be multiplexedthereon. The address/control block 902 may further be coupled to controlsignal lines 914 to further receive clock signals to synchronize addressand data and generate control signals at the appropriate moments. Inresponse to the input signals 913 and 914, the address/control block 902generates control signals 924 coupled to the data path buffer 904 tostore data into and/or write data out there-from. The address/controlblock 902 further generates control signals 922 coupled to themultiplexer/de-multiplexer 906 and the data path buffer 904 tosynchronously control their functional operations. The address/controlblock 902 further generates addresses and control signals onto a pair ofexternal address high/control buses 912A-912B for memory ranks zero andone, as well as address signals on the internal address bus 923 tocouple them into the multiplexer/de-multiplexer 906 for multiplexingonto the external address low/data bus 911 as required.

Some types of flash memory integrated circuits, such as NOR FLASH EEPROMintegrated circuits, may be configured so that read access times (wherean address is presented and data returned) may be reduced to levelssufficient for use in main memory of computer systems. However, read andwrite operations to flash memory may be asymmetric. A data writeoperation into flash memory may take much more time than a data readoperation from flash memory. A data erase operation in flash memory mayalso take much more time than a data read operation.

The data path buffer 904 may be used to store data so that the asymmetryin read and write operations with flash memory may be emolliated. Datamay be quickly written into the data path buffer 904 and then controlledto program large amounts of data into the flash memory at another momentin time. Similarly, a plurality of data read operations into flashmemory may be made with data being stored into the data path buffer 904.The data may be read out in bursts from the data path buffer.Additionally, signal timing differences between a data bus to the flashmemory die and an external data bus to the edge connector of a DIMM maybe emolliated by the buffering provided by the data path buffer 904. Forexample, the data bus 911 coupled to flash memory dice and consequentlyinternal data bus 921 may have data clocked in/out every twentynano-seconds (ns) while the data bus 916 coupled to the edge connectormay have data clocked in and out data every five nano-seconds. Thebuffering provided by the data path buffer 904 can smoother over thesetiming differences so they are transparent to each of the flash memorydice coupled to bus 911 and the devices coupled to bus 916 through theedge connector.

The data path buffer 904 is a data buffer includes memory, registers orother data storage means for each data bus 916 and 921 coupled to it toprovide the buffering.

The parallel bits (e.g., eight) of the data bus 916 coupled into thedata path buffer 904 may be less than the parallel bits (e.g.,thirty-two) of internal data bus 921 coupled to themultiplexer/de-multiplexer 906. The data path buffer 904 facilitatespacking data into wider bit widths for storage into one or more flashmemory parts and unpacking the wide data bytes read out from one or moreflash memory parts into narrower data bytes for reading over a fewernumber of bits of the external memory input/output data bus 916.

The multiplexer/de-multiplexer 906 is coupled to the data buffer 904over the internal data bus 921 and the address and control block 902over the internal address bus 923. The multiplexer/de-multiplexer 906further receives control signals 922 from the address and control block902 to control its multiplexing/demultiplexing functions. Themultiplexer/de-multiplexer 906 is further coupled to the multiplexedaddress low/data bus 911 that is coupled to flash memory dice.

The multiplexer/de-multiplexer 906 includes a many-to-one busmultiplexer and a one-to-many bus de-multiplexer jointly functioningsimilar to a cross-bar switch. A cross-bar switch may be alternativelyused to implement the functions of the many-to-one bus multiplexer andthe one-to-many bus de-multiplexer.

The many-to-one bus multiplexer allows a large amount of data to be readaccessed in parallel, and then transferred out through the data pathbuffer 904 over a narrower data bus in a burst of cycles. Theone-to-many bus demultiplexer in conjunction with the data path buffer904 may be used over a burst of cycles to receive parallel data of anarrower width from the external data bus and to write out theaggregated data out to the flash memory die.

The bus multiplexing provided by the multiplexer/de-multiplexer 906allows extra flash memory dice to be stacked up behind the ASIC supportchip on each side of the DIMM so that is has a greater memory capacityavailable than otherwise possible without the support chips. The use ofthe memory support ASIC chip avoids adding extra capacitive loading ontoa memory channel bus from the extra flash memory dice in the memorymodule.

The clock/status block 908 is coupled to the data path buffer 904 toreceive control signals and status information 925 regarding data beingwritten out from the support ASIC 900 onto the external memory datainput/output bus 916. The clock/status block 908 further receives inputcontrol signals 919. The clock/status block 908 may generate clocksignals 918 to couple to the flash memory dice to synchronize the signaltiming on the buses 911 and 912A-912B coupled to the flash memory dice.The clock/status block 908 further generates data synchronization clocksand a ready/busy signal(s) 917 to be provided over the edge connector tosynchronize the signal timing on the data bus 916 for data driven outfrom the data path buffer 904.

The ready/busy signal(s) of the control signals 917 is a status signaland provides status of a requested operation with the flash memory. Theready/busy signal may be generated by the clock/status block 908 of thesupport ASIC 900 so that so that the flash memory dice may be moreefficiently accessed. The status signal may indicate whether or not theflash memory coupled to the support ASIC is busy or ready for anotherwrite or erase access to alleviate the non-deterministic nature of eraseand write operations to flash memory. The control input signals 919 maybe used to determine what information a support ASIC die reports in theclock/status block 908.

In one implementation, the memory support ASIC is integrated with flashmemory into a multi-chip package (MCP).

Referring now to FIG. 7A, a side cutaway view of a multi-chip packagedflash memory/support ASIC part 700A is illustrated. Previously,multi-chip packages may have been referred to as hybrid packages ormulti-chip module packages. Mounted in the package 701A is a top flashmemory die 118′, a combined spacer/memory support ASIC die 702, and alower flash memory die 118′.

The spacer/memory support ASIC die 702 includes a spacer 712 in a middleportion and active devices 704A-704B near outer portions beyond thedimensions of the top and bottom flash memory die 118′. The spacer 712may be a dielectric or insulator so that the active devices 704A-704B ofthe spacer/memory support ASIC die 702 do not short to any circuitry ofthe flash memory die 118′. Otherwise, the middle portion does notinclude any active devices or metal routing near its surfaces so that itcan act as a non-shorting spacer to the top and bottom flash memory die.Metal routing or interconnect may be buried and insulated in the spacer712 in the middle portion of spacer/memory support ASIC die 702 tocouple active devices 704A-704B in the outer portions together.

Conductors 705A-705B may couple the top flash memory die 118′ to theactive portions 704A-704B of the memory support ASIC die 702. Conductors706A-706B may couple the bottom flash memory die 118′ to the activeportions 704A-704B of the combined spacer/memory support ASIC die 702.Conductors 714A-714B may couple the combined spacer/memory support ASICdie 702 to pin-out connections 750. Conductors 715-716 may respectivelycouple the top and bottom flash memory die 118′ to the pin-outconnections 750.

An encapsulant 721 may be used to protect the devices mounted in thepackage 701A and keep conductors from shorting to each other.

Referring now to FIG. 7B, a side cutaway view of a multi-chip packagedflash memory/support ASIC part 700B is illustrated. Mounted in themulti-chip module package 701B is a memory support ASIC die 703, andpairs of a spacer and a flash memory die including a first spacer 722Aand a first flash memory die 118′, a second spacer 722B and a secondflash memory die 118′, a third spacer 722C and a third flash memory die118′, and an Nth spacer 722N and an Nth flash memory die 118′ stackedtogether as shown.

The spacer 722A may be the size of the support ASIC 703 as shown orsomewhat smaller than the size of the flash memory 118′ so that contactsmay be made to the support ASIC die 703 and the first flash memory die118′. The flash memory die 118′ is larger than the spacers 722B-722N toprovide an opening into a perimeter of the flash memory dice 118′ sothat electrical connections may be made.

In other implementations, the spacer may be applied after a flash die118′ is connected to a substrate of the package. The spacer may coverthe areas on the flash memory die 118′ to which it was connected.

The spacers 722A-722N may be a dielectric or insulator so that thememory support ASIC die 703 and flash memory dice 118′ do not short outto each other. Otherwise, the spacers do not include any active devicesor metal routing, unless buried under the surface, so that it will notshort wires or signal lines together.

The support ASIC and the flash memory dice 118′ may be coupled togetherat joint package pads/pins 750J. For example, conductors 705A and 705Bmay couple signals of the support ASIC die 703 to a connection on thetop flash memory die 118′ and thence to the joint package pads 750J bymeans of conductors 710A and 711A respectively. Connections on otherlevels of flash memory die 118′ may couple to the same joint package pad750J by conductors 710B-710N and 711B-711N respectively. That is, theother flash memory dies 118′ are connected to the ASIC die by way ofmultiple connections to the joint package pads/pins 750J.

The memory support ASIC 703 and each flash memory dice 118′ may directlyand independently couple to independent package pads/pins 750I of thepackage. For example, the support ASIC die 703 may couple to independentpackage pads/pins 750I by means of conductors 706A-706N and 708. The Nflash memory dice 118′ may directly and independently couple to theirown respective independent package pads/pins 750I by means of conductors707A-707N. The conductors 707A-707N coupled to the respectiveindependent package pads/pins 750I may be a chip enable signal toactivate the flash memory die or not.

An encapsulant 721 may also be used to protect the devices mounted inthe package 701B and keep conductors from shorting to each other.

The FMDIMMs descried herein may be used to swap out one or more DRAMmemory modules in a memory channel to reduce average power consumptionin main memory of a system. In this case, the FMDIMMs are plugged intothe one or more sockets replacing DRAM memory modules in the respectivememory channel.

Certain exemplary embodiments of the invention have been described andshown in the accompanying drawings. It is to be understood that suchembodiments are merely illustrative of and not restrictive on the broadinvention, and that the embodiments of the invention not be limited tothe specific constructions and arrangements shown and described.

For example, the flash memory DIMMs were described herein andillustrated with reference to bit widths of address busses, bit widthsof data busses, and in some instances, bit widths of control busses.However, the embodiments of the invention may be applied to a wide rangeof bit widths of address busses, data busses, and control busses, andtherefor must not be so limited.

Moreover, the flash memory DIMMS were described herein as having amultiplexed address low/data bus. Other implementations may not sharethe address low bits on the data bus but may increase the size of theaddress high/control bus to carry the entire address separate from thedata bus

Additionally, the flash memory DIMMS were described herein as sharingthe address high bus between memory ranks on the FMDIMM. Otherimplementations may not share the address high bus between ranks but mayhave separate address busses for each rank of memory on the FMDIMM.

While flash memory DIMM has been used to describe the embodiments of theinvention, the embodiments of the invention may be applied to any memorymodule incorporating a non-volatile memory device.

Rather, the embodiments of the invention should be construed accordingto the claims that follow below.

What is claimed is:
 1. A flash memory dual inline memory module (DIMM)comprising: a printed circuit board with an edge connector, the printedcircuit board having a front side and a back side; a first plurality ofmulti-chip packaged flash memory/support application specific integratedcircuit (ASIC) parts mounted to the front side of the printed circuitboard and electrically coupled to the edge connector, each of the firstplurality of multi-chip packaged flash memory/support ASIC parts havinga front side flash memory, a memory support ASIC, and a front/backcontrol signal coupled to a first power supply to select a front sidepinout of the memory support ASIC; a second plurality of multi-chippackaged flash memory/support application specific integrated circuit(ASIC) parts mounted to the back side of the printed circuit board andelectrically coupled to the edge connector, each of the second pluralityof multi-chip packaged flash memory/support ASIC parts having a backside flash memory, a memory support ASIC, and a front/back controlsignal coupled to a second power supply to select a back side pinout ofthe memory support ASIC that mirrors the front side pinout of the memorysupport ASIC; and a first address device mounted to the printed circuitboard and electrically coupled to the edge connector and the firstplurality of multi-chip packaged flash memory/support ASIC parts.
 2. Theflash memory DIMM of claim 1, further comprising: a plurality of firstmetal traces on one or more layers of the printed circuit board, theplurality of metal traces to electrically couple the edge connector andthe plurality of multi-chip packaged flash memory/support ASIC parts,and wherein the plurality of metal traces include traces for power,ground, and address and data signals.
 3. The flash memory DIMM of claim1, wherein the first power supply is a positive power supply to selectthe front side pinout of the memory support ASIC in each of the firstplurality of multi-chip packaged flash memory/support ASIC parts; andthe second power supply is a negative power supply to select the backside pinout of the memory support ASIC in each of the second pluralityof multi-chip packaged flash memory/support ASIC parts.
 4. The flashmemory DIMM of claim 3, wherein the negative power supply is ground. 5.The flash memory DIMM of claim 3, wherein the front/back control signalelectronically alters the pinout configuration of the memory supportASIC to provide the mirrored pinout.
 6. The flash memory DIMM of claim5, wherein the mirrored pinout reduces conductive traces on the printedcircuit board and the number of layers of conductive traces.
 7. A dualinline memory module (DIMM) comprising: a printed circuit board with anedge connector, the printed circuit board having a front side and a backside; a first plurality of integrated circuit parts mounted to the frontside of the printed circuit board and electrically coupled to the edgeconnector, each of the first plurality of integrated circuit partshaving a front/back control signal coupled to a first power supply toselect a front side pinout of an integrated circuit die within eachintegrated circuit part; and a second plurality of integrated circuitparts mounted to the back side of the printed circuit board andelectrically coupled to the edge connector, each of the second pluralityof integrated circuit parts having a front/back control signal coupledto a second power supply to select a back side pinout of an integratedcircuit die within each integrated circuit part; wherein the selectedback side pinout of the integrated circuit die within each of the secondplurality of integrated circuit parts mirrors the selected front sidepinout of the integrated circuit die within each of the first pluralityof integrated circuit parts.
 8. The DIMM of claim 7, wherein the firstpower supply is a positive power supply to select the front side pinoutof the integrated circuit die in each of the first plurality ofintegrated circuit parts; and the second power supply is a negativepower supply to select the back side pinout of the integrated circuitdie in each of the second plurality of integrated circuit parts.
 9. TheDIMM of claim 8, wherein the negative power supply is ground.
 10. TheDIMM of claim 7, wherein the front/back control signal electronicallyalters the pinout configuration of the integrated circuits to providethe mirrored pinout.
 11. The DIMM of claim 10, wherein the mirroredpinout reduces conductive traces on the printed circuit board and thenumber of layers of conductive traces.